Question 1

Which of the following best describes the main structural difference between bacterial and archaeal cytoplasmic membranes?

Accepted Answer

Bacterial membranes contain ester linkages and fatty acids, while archaeal membranes contain ether linkages and isoprenes.

Question 2

A Gram-positive bacterium is exposed to penicillin. Which component of its cell envelope is most directly affected, and why?

Accepted Answer

The peptidoglycan layer, because penicillin inhibits peptide cross-link formation.

Question 3

Which of the following is a function of the S-layer in prokaryotes?

Accepted Answer

Providing strength, protection from lysis, and facilitating cell surface interactions.

Question 4

A bacterium is found to have a thick peptidoglycan layer, teichoic acids, and is susceptible to lysozyme. Which type of cell wall does it most likely possess?

Accepted Answer

Gram-positive

Question 5

Which of the following best explains why gas vesicles are advantageous to aquatic bacteria?

Accepted Answer

They confer buoyancy, allowing cells to position themselves optimally for light and nutrients.

Question 6

Which of the following statements about endospores is FALSE?

Accepted Answer

Endospores are produced by all bacteria during nutrient-rich conditions.

Question 7

Which of the following is a key difference between the cell walls of Bacteria and Archaea?

Accepted Answer

Bacteria have peptidoglycan, while Archaea may have pseudomurein or S-layers.

Question 8

A researcher observes a bacterium with a sticky, tightly attached matrix visible after India ink staining. What is this structure and its likely function?

Accepted Answer

Capsule; aids in surface attachment and virulence.

Question 9

Which of the following best describes the role of magnetosomes in certain bacteria?

Accepted Answer

They allow cells to orient and migrate along magnetic field lines.

Question 10

Which of the following is a correct sequence of events in endospore formation?

Accepted Answer

Cell division → Engulfment → Cortex formation → Maturation → Mother cell lysis

Question 11

Which of the following best explains why Gram-negative bacteria are generally more resistant to antibiotics like penicillin than Gram-positive bacteria?

Accepted Answer

Gram-negative bacteria have an outer membrane that restricts antibiotic entry.

Question 12

Which of the following is a function of pili in bacteria?

Accepted Answer

Facilitating genetic exchange through conjugation

Question 13

A bacterium is found to accumulate polyphosphate granules. What is the primary function of these inclusions?

Accepted Answer

Reservoir of inorganic phosphate for nucleic acid and phospholipid synthesis

Question 14

Which of the following best describes the composition of peptidoglycan?

Accepted Answer

Repeating units of N-acetylglucosamine and N-acetylmuramic acid cross-linked by peptides

Question 15

Which of the following is a unique feature of archaeal cell membranes compared to bacterial membranes?

Accepted Answer

Presence of phosphoglycerol diethers with phytanyl side chains

Question 16

Which of the following structures is most directly involved in the formation and maintenance of biofilms?

Accepted Answer

Capsules and slime layers

Question 17

A bacterium is found to be resistant to lysozyme and lacks peptidoglycan. Which type of cell wall does it most likely possess?

Accepted Answer

Archaeal with pseudomurein

Question 18

Which of the following best describes the function of small acid-soluble spore proteins (SASPs) in endospores?

Accepted Answer

They protect DNA from heat, desiccation, and UV radiation.

Question 19

Which of the following is a correct description of the permeability barrier function of the cytoplasmic membrane?

Accepted Answer

It prevents leakage and functions as a gateway for transport of nutrients into and wastes out of the cell.

Chapter Two

Study Guide - Practice Questions

Study Guide - Flashcards